Method for conversion of a color electronic pre-press system data file to a page description language data file

ABSTRACT

A method for the conversion of an CEPS image data file to a vector dominated Page Description Language (PDL) file. The CEPS image data file can include LineWork image data, Continuous Tone image data and High resolution Continuous Tone (HC) data. The Page Description Language file can be realized as a composite file or a separated file.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to image processing systems in general andin particular to a method for conversion of a Color Electronic Pre-pressSystem (CEPS) image data file to a Page Description Language (PDL) file.

It is well known that an image data file prepared on a Color ElectronicPre-press System (CEPS) cannot be exposed on a PostScript-only outputdevice. Generally speaking, the incompatibility between CEPS image datafiles and PostScript-only output devices derives from the format inwhich LineWork entries are stored in CEPS image data files as opposed toContinuous Tone image formats which are generally compatible withPostScript-only output devices.

Several approaches have been suggested to convert LineWork files of CEPSrun length encoded (RLE) raster formats into PostScript files. One suchapproach includes the recognition of characters and graphic elementsfrom the CEPS run length encoded (RLE) raster data and their subsequentconversion to equivalent PostScript vector representations. However,this approach suffers from several limitations including that it canhandle LineWork (LW) data only and the LineWork-Continuous Tone (LW-CT)interface is not addressed, it produces complex LW files of linearvectors which typically take a long time to convert and to Raster ImageProcessor (RIP), it does not produce separated PostScript (PS) filesdirectly, it does not handle High Resolution Continuous Tone (HCT) dataat all, and others. Another approach includes the conversion of aLineWork file and a Continuous Tone file into a single RLE image filewhich can be handled by a PostScript Level 2 Raster Image Processor.However, this approach typically leads to unacceptably long processingtimes due to data explosion because of the high resolution of rasterscanning, typically, in the order of 100 lines per mm.

There is therefore a need for a method for conversion of a ColorElectronic Pre-press System (CEPS) image data file to a vector dominatedPage Description Language (PDL) file.

SUMMARY OF THE INVENTION

The present invention is for a method for the conversion of a ColorElectronic Pre-press System (CEPS) image data file to a vector dominatedPage Description Language (PDL) file.

Hence, there is provided according to a first aspect of the presentinvention, a method of converting an CEPS LineWork image data file to acomposite Page Description Language (PDL) file, the CEPS LineWork imagedata file including a LineWork image made up of a multiplicity ofLineWork run length encoded (RLE) entries, the method comprising thesteps of: (a) importing a portion of the LineWork image data file intothe memory; (b) reading parameters from the portion of the LineWorkimage data file associated with the dimensions and resolution of theLineWork image; (c) preparing the composite PDL file according to theparameters from step (b); (d) reading a plurality of LineWork RLEentries from the CEPS LineWork image data file; (e) sorting theplurality of Linework RLE entries by color into clusters of Linework RLEentries; (f) translating each cluster of LineWork RLE entries into atleast one PDL element; and (g) exporting each PDL element to thecomposite PDL file.

According to a further feature of the present invention, the PDL elementis realized as a concatenation of horizontal line segments.

According to a still further feature of the present invention, the PDLelement is realized as a rectangle.

According to a yet still further feature of the present invention, theclusters are sorted such that the cluster of the color having thegreatest number of RLE entries is applied as a background color.

According to a yet still further feature of the present invention, theplurality of LineWork RLE entries is read from all the CEPS LineWorkimage data file.

According to a yet still further feature of the present invention, theCEPS LineWork image data file includes a LineWork color mapping table,the LineWork color mapping table having a multiplicity of color indices,the method further comprising the step of preparing an internal colormapping table from the LineWork color mapping table in which colorssharing the same CMYK values in the LineWork color mapping table aregiven the same color index in the internal color mapping table such thatthe step of sorting is by color index of the internal color mappingtable.

According to a yet still further feature of the present invention, themethod further comprising the step of defining the number of LineWorklines in a band and repeating steps (d) to (g) for each band such thatall the LineWork image data file is read.

According to a yet still farther feature of the present invention, themethod further comprising the step of matching the resolution of theLineWork image data file with the resolution of an output device onwhich the composite PDL file is to be exposed.

According to a yet still further feature of the present invention, themethod further comprising the step of matching the user space of thecomposite PDL file with the device space of the output device.

There is also provided according to a second aspect of the presentinvention, a method of converting an CEPS LineWork image data file to aseparated Page Description Language (PDL) file, the separated PDL fileincluding a page for each CMYK separation, the CEPS LineWork image datafile including a LineWork image made up of a multiplicity of LineWorkRLE entries, the method comprising the steps of: (a) importing a portionof the LineWork image data file into the memory; (b) reading parametersfrom the portion of the LineWork image data file associated with thedimensions and resolution of the LineWork image; (c) preparing theseparated PDL file according to the parameters from step (b); (d)reading a plurality of LineWork RLE entries from the CEPS LineWork imagedata file; (e) preparing at least one cluster of LineWork RLE entriesfor each CMYK component separately, each of the at least one clusterbeing dedicated to a particular value for that CMYK separation color;(f) translating each cluster of LineWork RLE entries into at least onePDL element; and (g) exporting each PDL element to its correspondingCMYK script section of the separated PDL file.

According to a further feature of the present invention, the PDL elementis realized as a concatenation of horizontal line segments.

According to a still further feature of the present invention, the PDLelement is realized as a rectangle.

According to a yet still further feature of the present invention, theplurality of LineWork RLE entries is read from all the CEPS LineWorkimage data file.

According to a yet still further feature of the present invention, themethod further comprising the step of defining the number of LineWorklines in a band and repeating steps (d) to (g) for each band such thatall the LineWork image data file is read.

According to a yet still further feature of the present invention, themethod farther comprising the step of matching the resolution of theCEPS LineWork image data file with the resolution of an output device onwhich the separated PDL file is to be exposed.

According to a yet still further feature of the present invention, themethod further comprising the step of matching the user space of theseparated PDL file with the device space of the output device.

According to a yet still further feature of the present invention, theat least one cluster are sorted for each CMYK component such that thecluster of the value of the CMYK separation color having the greatestnumber of RLE entries is applied as a background color.

There is also provided according to a third aspect of the presentinvention, a method of converting an CEPS page described by a LineWorkimage data file and a Continuous Tone image data file to a compositePage Description Language (PDL) file, the LineWork image data fileincluding a LineWork image made up of multiplicity of LineWork runlength encoded (RLE) entries of which at least one entry has atransparent color value associated with a Continuous Tone image, themethod comprising the steps of: (a) importing a portion of theContinuous Tone image data file into a memory; (b) reading parametersfrom the portion of the Continuous Tone image data file associated withthe position, dimensions and resolution of the Continuous Tone image;(c) importing a portion of the LineWork image data file into the memory;(d) reading parameters from the portion of the LineWork image data fileassociated with the dimensions and resolution of the LineWork image; (e)preparing the composite PDL file according to the parameters from steps(b) and (d); (f) transferring Continuous Tone image data from theContinuous Tone image data file to the composite PDL file; (g) reading aplurality of LineWork RLE entries from the LineWork image data file; (h)sorting the plurality of Linework RLE entries by color into clusters ofLinework RLE entries; (i) translating each cluster of LineWork RLEentries into at least one PDL element except for the clusters havingtransparent color values; and (j) exporting each PDL element to thecomposite PDL file.

According to a further feature of the present invention, the PDL elementis realized as a concatenation of horizontal line segments.

According to a still further feature of the present invention, the PDLelement is realized as a rectangle.

According to a yet still further feature of the present invention, theclusters are sorted such that the cluster of the color having thegreatest number of RLE entries is applied as a background color in allareas except for transparent areas.

According to a yet still further feature of the present invention, theplurality of LineWork RLE entries is read from all the LineWork imagedata file.

According to a yet still further feature of the present invention, theLineWork image data file includes a LineWork color mapping table, theLineWork color mapping table having a multiplicity of color indices, themethod further comprising the step of preparing an internal colormapping table from the LineWork color mapping table in which opaquecolors sharing the same CMYK values in the Linework color mapping tableare given the same color index in the internal color mapping table suchthat the step of sorting is by color index of the internal color mappingtable.

According to a yet still further feature of the present invention, themethod further comprising the step of defining the number of LineWorklines in a band and repeating steps (g) to (j) for each band such thatall the LineWork image data file is read.

According to a yet still further feature of the present invention, themethod further comprising the step of matching the resolution of theLineWork image data file with the resolution of an output device onwhich the composite PDL file is to be exposed.

According to a yet still further feature of the present invention, themethod further comprising the step of matching the user space of thecomposite PDL file with the device space of the output device.

There is also provided according to a fourth aspect of the presentinvention, a method of converting an CEPS page described by a LineWorkimage data file and a Continuous Tone image data file to a separatedPage Description Language (PDL) file, the LineWork image data fileincluding a LineWork image made up of multiplicity of LineWork RLEentries of which at least one entry has a transparent color valueassociated with a Continuous Tone image, the method comprising the stepsof: (a) importing a portion of the Continuous Tone image data file intoa memory; (b) reading parameters from the portion of the Continuous Toneimage data file associated with the position, dimensions and resolutionof the Continuous Tone image; (c) importing a portion of the LineWorkimage data file into the memory; (d) reading parameters from the portionof the LineWork image data file associated with the dimensions andresolution of the LineWork image; (e) preparing the separated PDL fileaccording to the parameters from steps (b) and (d); (f) transferring theContinuous Tone image data from the Continuous Tone image data file tothe separated PDL file for the first of the CMYK components; (g) readinga plurality of LineWork RLE entries from the LineWork image data file;(h) preparing at least one cluster of LineWork RLE entries for the CMYKcomponent selected in step (f), each of the at least one cluster beingdedicated to a particular value for that CMYK separation color; (i)translating each cluster of LineWork RLE entries into at least one PDLelement except for clusters having transparent color values in thatseparation; (j) exporting each PDL element to its corresponding CMYKscript section of the separated PDL file; and (k) repeating steps (f)through (j) for the other CMYK components.

According to a further feature of the present invention, the PDL elementis realized as a concatenation of horizontal line segments.

According to a still further feature of the present invention, the PDLelement is realized as a rectangle.

According to a yet still further feature of the present invention, theplurality of LineWork RLE entries is read from all the LineWork imagedata file.

According to a yet still further feature of the present invention, themethod further comprising the step of defining the number of LineWorklines in a band and repeating steps (g) to (j) for each band such thatall the LineWork image data file is read.

According to a yet still further feature of the present invention, themethod further comprising the step of matching the resolution of theLineWork image data file with the resolution of an output device onwhich the separated PDL file is to be exposed.

According to a yet still further feature of the present invention, themethod further comprising the step of matching the user space of the PDLfile with the device space of the output device.

According to a yet still further feature of the present invention, theat least one cluster are sorted for each CMYK component such that thecluster of the value of the CMYK separation color having the greatestnumber of RLE entries is applied as a background color in all areasexcept for the transparent areas.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, withreference to the accompanying drawings, wherein:

FIG. 1 illustrates a raster LineWork image including graphical elements;

FIG. 2 illustrates an CEPS LineWork image data file with code describingthe image of FIG. 1;

FIG. 3 illustrates a native composite PostScript file describing a pagerepresented by the LineWork image of FIG. 1;

FIGS. 4A-4B illustrate a native separated PostScript file describing apage represented by the LineWork image of FIG. 1;

FIG. 5 illustrates a raster image including graphical elements and aContinuous Tone (CT) image;

FIG. 6 illustrates an CEPS image data file with code describing theimage of FIG. 5;

FIG. 7 illustrates a native composite PostScript file describing a pagerepresented by the image of FIG. 5;

FIGS. 8A-8C illustrate a native separated PostScript file describing apage represented by the image of FIG. 5;

FIGS. 9A-9B illustrate the output composite PostScript file describingthe LineWork image of FIG. 1 after conversion from the input CEPSLineWork image data file illustrated in FIG. 2 according to theteachings of the present invention;

FIGS. 10A-10C illustrate a technique for color mapping and thesubsequently modified output composite PostScript file;

FIGS. 11A-11C illustrate a technique for scanning the input CEPS imagedata file band-by-band and the subsequently modified output compositePostScript file;

FIGS. 12A-12B illustrate a technique for matching the resolution of theinput CEPS image data file to the resolution of an output device and thesubsequently modified output composite PostScript file;

FIGS. 13A-13D illustrate the output separated PostScript file describingthe LineWork image of FIG. 1 after conversion from the input CEPSLineWork image data file illustrated in FIG. 2 according to theteachings of the present invention;

FIGS. 14A-13C illustrate the output composite PostScript file describingthe image of FIG. 5 after conversion from the input CEPS image datafiles (LW and CT) illustrated in FIG. 6 according to the teachings ofthe present invention; and

FIGS. 15A-15F illustrate the output separated PostScript file describingthe image of FIG. 5 after conversion from the input CEPS image datafiles (LW and CT) illustrated in FIG. 6 according to the teachings ofthe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is of a method for the conversion of a ColorElectronic Pre-press System (CEPS) image data file to a vector dominatedPage Description Language (PDL) file.

The principles and operation of the method according to the presentinvention may be better understood with reference to the drawings andthe accompanying description.

For the sake of the better understanding of the principles and theoperation of the present invention, the manner in which an CEPS imagedata file and a Page Description Language file represent the same imageis now described with reference to an 20×20 image, generally designated10, shown in FIG. 1. It should be noted that the term CEPS image fileimplies both image data files prepared on CEPS systems, such as Scitexsystems, and also image data files prepared according to the TIFF/ITstandard described in ANSI IT8.8. Furthermore, it should be noted thatthe term Page Description Language file implies both physical files andto a stream of Page Description Language code transmitted to a RIP, acomputer, a workstation, and the like.

As can be clearly seen, image 10 includes only non-continuous toneLineWork elements including the following elements: a white background12, a blue triangle 14, a red rectangle 16, a red square 18, a bluetriangle 20 and a red rectangle 22. The resolution of elements 10-22 istypically between 2000-3000 dpi. Elements 10-22 are shaded according toa color scheme of color indices 1-6, respectively. In this case, colorindex 1 represents the color white, color indices 2 and 5 represent thecolor blue and color indices 3, 4 and 6 represent the color red. Itshould be noted that the practice of providing more than one color indexfor the same color facilitates better control during electronic pagemake-up as known in the art. As can be clearly seen, FIG. 1 alsoillustrates the CMYK separations of image 10.

With reference now to FIG. 2, a typical CEPS LineWork image data file 24representing image 10 includes a LineWork color mapping table 26detailing the CMYK values of the color indices 1-6 and a list 28detailing each line of the 20 lines of image 10 in a top-to-bottomsequence using the top left hand corner of image 10 as the origin (0,0).In particular, LineWork color mapping table 26 illustrates that the CMYKvalues of the color indices 1-6 are as follows: (0,0,0,0) for white asrepresented by color index 1, (255,255,0,0) for blue as represented bycolor indices 2 and 5 and (0,255,255,0) for red as represented by colorindices 3, 4 and 6. It should be noted that CEPS LineWork data file 24is illustrated in schematic form whereas in actual fact data files arebinary encoded and are more complicated in the sense that they alsoinclude more parameters in the header, restrictions on the length of theruns, and the like.

Each line of list 28 includes one or more run length encoded (RLE)entries. Each entry is in the format (a,b) where "a" represents thecolor index of the RLE entry and "b" represents the length of the RLEentry. Run Length Encoding is a well known method for raster datacompression. Hence, Line 0 includes just a single RLE entry (1,20)indicative of the single white stroke extending across the width ofimage 10 while Line 4 includes four RLE entries (1,4)(3,10)(2,3)(1,3)indicative of a 4 pixel long white stroke, a 10 pixel long red stroke, a3 pixel long blue stroke and a 2 pixel long white stroke. Hence, for thesake of clarity, triangle 14 is represented by four RLE entries on Lines2, 3, 4 and 5. For more details of CEPS image data files, reference ismade to the Scitex Handshake File Format Specification which isincorporated herein by reference as if fully set forth herein.

With reference now to FIGS. 3 and 4, native PostScript (PS) files 30 and32 describe the page represented by image 10 according to a compositePostScript script format and a separated PostScript script format,respectively. It should be noted that the term native implies thatPostScript files 30 and 32 are generated by an DTP application on an DTPsystem. As is well known in the art, PostScript is a Page DescriptionLanguage (PDL) developed by Adobe Systems Ltd. For more details ofPostScript, reference is made to PostScript Language Reference Manual,2nd Ed. ISBN 0-201-18127-4 which is incorporated herein by reference asif fully set forth herein.

The basic difference between native composite PostScript file 30 andnative separated PostScript file 32 is that native composite PostScriptfile 30 represents image 10 element by element for the four CMYKseparations together while native separated PostScript file 32represents image 10 for each CMYK separation separately. For the sake ofclarity, the difference between native composite PostScript file 30 andnative separated PostScript file 32 can be better understood by thefollowing brief notes.

Turning now to FIG. 3, native composite PostScript file 30 includes aprolog section 34, a set-up section 36 and a script section 38. Prologsection 34 includes general definitions (dictionaries). Set-up section36 includes commands, parameters and definitions for that specific page.Examples, a command for instructing the use of the top left hand cornerof an image as the origin (0,0) of the y axis rather than theconventional use of the bottom left hand corner of an image and the CMYKvalues of the color indices 1-6 in a similar fashion to LineWork colormapping table 26. In the file shown, the command maps the LineWorkcoordinate system onto the PostScript device coordinate system. Scriptsection 38 typically includes two types of operators for representingthe actual page elements: the first type of operators are vectoroperators, for example, moveto, lineto, closepath, and the like whichdefine a single line or a closed geometrical shape while the second typeof operators are painting operators, for example, fill, stroke, and thelike for applying color to either the line or the closed geometricalshape. Typically, the last operator of a PostScript page is the operatorshowpage.

Script section 38 includes six script sub-sections 38a, 38b, 38c, 38d,38e and 38f for each of the color indices 1 to 6. Script sub-sections38a to 38f are superimposed in their top-to-bottom sequence in nativecomposite PostScript file 30 to establish the single montage of image10. Hence, the top right hand section of rectangle 16, represented bythe command lines:

I3 setcolor

4 4 M 14 4 L 14 8 L 4 8 L closepath

fill,

superimposes over the bottom left hand corner of triangle 14,represented by the command lines:

I2 setcolor

14 2 M 17 5 l 11 5 L closepath

fill

Turning now to FIG. 4, native separated PostScript file 32 includesprolog section 40, a set-up section 42, a section 44 for the cyanseparation, a section 46 for the magenta separation, a section 48 forthe yellow separation and a section 50 for the black separation. Each ofsections 44, 46, 48 and 50 includes a set-up section denoted "a" inwhich a value is given for each of the colors appearing in the page foreach CMYK separation and a script section denoted "b" including vectorrepresentations for each of elements 12-22. In other words, for the sakeof clarity, section 44 for the cyan separation includes a set-up section44a representing the cyan component percentage for each of color indices1-6 and a script section 44b including the six vector representationsfor square 12, triangle 14, rectangle 16, square 18, triangle 20 andrectangle 22. Typically, the last operator in each of sections 44, 46,48 and 50 is the operator showpage.

Thus, in native separated PostScript file 32, rectangle 16 isrepresented by the command lines

I3 setcolor

4 4 M 14 4 L 14 8 L 4 8 L closepath

fill

in cyan script section 44b, magenta script section 46b, yellow scriptsection 48b and black script section 50b. The difference being that thevalue of the red color is different for each of the CMYK separations. Inparticular, for the color indices 3, 4 and 6, the value of the red coloris 1,0,0,1 for set-up sections 44a, 46a, 48a and 50a, respectively. In asimilar fashion, for the color indices 2 and 5, the value of the bluecolor is 0,0,1,1 for set-up sections 44a, 46a, 48a and 50a,respectively. As known in the art, the value of each CMYK separation cantake any intermediate value between the solid value of 0 and the allwhite value of 1. It should be noted that color definitions in CMYKcolor space used in composite files have an inverse "polarity" to theGRAY color space used in separated files.

With reference now to FIGS. 5-8, to develop the example further, one ofelements 12-22, in this case rectangle 16, is shown as an CT image 52 toform a new page, generally designated 54, in FIG. 5. CT image 52 istypically a scanned image and/or a vignette having a resolution of about300 dpi. In certain cases, High resolution Continuous tone (HC) data isemployed for the boundary between a LineWork element and an CT image, inthis case, triangle 14 and CT image 52. Also, HC data is often employedfor the boundary between two CT images. The manner in which CEPSLineWork image data file 24, native composite PostScript file 30 andnative separated PostScript file 32 are modified to represent page 54are described with reference to FIGS. 6, 7 and 8, respectively.

Turning now to FIG. 6, page 54 requires both an CEPS LineWork image datafile 56 and an CEPS Continuous Tone image data file 58 of raster imagedata. As described with reference to CEPS LineWork data image file 24,CEPS LineWork data image file 56 includes a LineWork color mapping table60 and a list 61 detailing each line of the 20 lines of page 54. Thedifference between LineWork color mapping table 60 and LineWork colormapping table 26 is that the red color identified by color index 3 isclassed as a transparent color denoted T indicating that the pixels onLines 4-7 painted this color should be left transparent to CT image 52when exposed on an CEPS system. As is well known in the art, there aretwo types of transparent colors: fall transparent colors in which an CTimage is visible in all CMYK separations and semi-transparent colors inwhich an CT image is visible in some of the CMYK separations while it issuperimposed by LineWork data in the remaining CMYK separations. In thepresent case, the red color identified by color index 3 is a fulltransparent color.

Turning now to FIG. 7, page 54 is described by a native compositePostScript file 62 including a prolog section 64, a set-up section 66, ascript section 68 and a Continuous Tone image section 70 in the form ofraster image data taken from CT file 58. The differences between nativecomposite PostScript file 62 and native composite PostScript file 30 areas follows. First, set-up section 66 does not include the CMYK values ofthe color index 3. And second, script section 68 does not include avector representation of rectangle 16 to be painted by the red colorindicated as color index 3. Hence, script section 68 includes fivesub-sections 68a, 68b, 68d, 68e and 68f for color indices 1, 2, 4, 5 and6 and not six sub-sections as does composite PostScript file 32 by notincluding a sub-section 68c for color index 3. Rather, the vectorrepresentation of rectangle 16, namely "4 4 M 14 4 L 14 8 L 4 8 Lclosepath", is used in Continuous Tone image section 70 to define aclipping path which acts as the perimeter within which CT image 52 isplaced.

Turning now to FIG. 8, page 54 is described by a native separatedPostScript file 72 including a prolog section 74, a set-up section 76and four sections 78, 80, 82 and 84 for the four CMYK separations. Inthis case, sections 78, 80, 82 and 84 include information regarding bothelements 12-22 and CT image 52. The differences between, for example,cyan section 78 and cyan section 44 are as follows. First, cyan set-upsection 78a does not include the cyan value of the color index 3. Andsecond, cyan section 78 includes a cyan CT section 78c which includesthe vector representation of rectangle 16, namely "4 4 M 14 4 L 14 8 L 48 L closepath", for defining a clipping path which acts as the perimeterwithin which the cyan data of CT image 52 is placed.

With reference now to FIG. 9, the method for conversion of an input CEPSimage data file, for example, CEPS LineWork image data file 24, to anoutput composite PostScript file 100 according to the teachings of thepresent invention is now described with reference to image 10. Generallyspeaking, output composite PostScript file 100 has a similar format tonative composite CEPS LineWork file 30 in that it includes a prologsection 102, a set-up section 104 and a script section 106. However, itshould be noted that for the sake of clarity, the code shown in FIG. 9and thereafter is the most elementary form embodying the principles ofthe present invention. In practice, the code will be more complicated inthe sense that it will employ dictionaries, loops, binary encoding andother standard PostScript techniques and features.

Broadly speaking, the conversion is achieved by vectorizing the RLEentries in CEPS LineWork image data file 24 to PostScript elements byvirtue of a novel use of PostScript operators. Although the method isdescribed with particular reference to PostScript, it should be readilyunderstood that the teachings of the present invention can be readilyapplied to a wide range of other commercially available vector dominatedPage Description Languages including, but not limited to, Interpress,Adobe Acrobat Portable Document Format (PDF), and the like.

The first step of the conversion includes importing CEPS LineWork imagedata file 24 into a memory and extracting parameters from CEPS LineWorkimage data file 24 required for preparation of prolog section 102 andset-up section 104 of output composite PostScript file 100. Suchparameters typically include page set-up details including, but notlimited to, LW image height, LW image width, and LW image resolution.Preferably, the first step of conversion includes importing LineWorkcolor mapping table 26, if available.

The second step of the conversion involves reading a plurality ofLineWork RLE entries from CEPS LineWork image data file 24. Theplurality of LineWork RLE entries can be read from all of file 24 orfrom part of file 24, known as a band of several lines, as describedbelow in greater detail with reference to FIG. 11.

The third step of the conversion involves sorting the plurality of RLEentries by LineWork color into clusters of RLE entries such that eachcluster includes all the RLE entries associated with one of the LineWorkcolors inherent to image 10. In the present instance, six clusters wouldbe obtained for each of the colors 1 to 6. Hence, for example, thecluster associated with color 2 representative of triangle 14 includesthe following RLE entries: Line 2(2,1), Line 3(2,3), Line 4(2,3) andLine 5(2,4). Furthermore, the clusters include information determiningthe x coordinates of the RLE entries. Alternatively, the sorting of RLEentries can be by color index if LineWork color mapping table 26 isavailable.

The fourth step of the conversion involves translating each cluster ofRLE entries into one or more PostScript elements. Typically, thePostScript elements are either concatenations of horizontal linesegments or rectangles. Concatenations of horizontal line segments,known as "paths" in PostScript, can include up to 1500 sub-paths i.e.1500 line segments. Each sub-path is defined by a start point and an endpoint or, alternatively, by a start point and a vector length. The startpoints are defined in terms of (x,y) co-ordinates from (0,0). In thecase of rectangles, each rectangle is defined as a closed geometricalshape by four vectors in a similar fashion to the PostScript descriptionof elements 12, 16 and 22 as described with reference to FIGS. 3 and 4.Alternatively, rectangles can be defined by any other standard rectanglerepresentation in PostScript. The decision as to whether the RLE entriesshould be translated into a concatenation of horizontal line segments orrectangles depends on a number of factors including, the number of RLEentries in each cluster, whether an RLE entry extends across theLineWork page, and the presence of transparent colors for images. Itshould be noted that in some cases a technical correction is requiredwhen paths and rectangles appear on the same page. This correction isachieved by means of a small translation along the y axis when arectangle is executed.

In the present instance, script section 106 of output compositePostScript file 100 indicates that the clusters of RLE entriesassociated with colors 2, 3, 4 and 5 are translated into paths includingone or more sub-paths while the clusters of RLE entries associated withcolors 1 and 6 are translated into rectangles. It should be noted thatthe cluster of RLE entries associated with color 1 is preferablytranslated into a rectangle covering the whole page and not a path so asto provide the background of image 10. The color, in this case white, isselected because its cluster of RLE entries has the greatest number ofRLE entries. In other words, the color of the cluster having thegreatest number of RLE entries is preferably defined as the backgroundcolor in the output PostScript file.

The clusters of RLE entries associated with colors 2-5 are translatedinto paths including four sub-paths, four sub-paths, four sub-paths andtwelve sub-paths, respectively. As mentioned hereinabove, each sub-pathis defined by an operator determining the (x,y) start point of thesub-path and, in this case, an operator determining the length of thesub-path. Hence, for the sake of clarity, triangle 14 is translated intoa path 14 2 M 1 0 RL, 13 3 M 3 0 RL, 14 4 M 3 0 RL and 14 5 M 4 0 RL inoutput composite PostScript file 100 in contrast to its vectorizedgeometrical representation in native composite PostScript file 30. Theother elements in image 10, namely, rectangle 16, square 18 and triangle20 are translated in a similar fashion as triangle 14.

The translation of rectangle 16 into a path and rectangle 22 into arectangle is by virtue of rectangle 22 being recognized as a rectanglein image 10 because it extends across the width of the page of image 10while rectangle 16 is not recognized as a rectangle in image 10. Hence,the representation of rectangle 22 in output composite PostScript file100 is similar to its representation in native composite PostScript file30.

The fifth and last step of the conversion is the exporting of the PDLelements to output composite PostScript file 100. As mentionedhereinabove, output composite PostScript file 100 can be a physical fileor, alternatively, it can be a stream of Page Description Language codetransmitted to a RIP, a computer, a workstation, and the like.

With reference now to FIGS. 10-12, the method described hereinabove canbe refined by optimization algorithms to achieve a number of operationaladvantages, for example, a more compact PostScript file, a shorterconversion processing time, shorter RIPping time, better RIPping outputquality and the like.

Turning now to FIG. 10, the conversion can include the generation of aninternal color mapping table 108 in which color indices in LineWorkcolor mapping table 26 which share common CMYK values are regarded asthe same color in output composite PostScript file 100. Hence, in thepresent instance, the blue color represented by the color indices 2 and5 are combined into a single color index 2 in internal color mappingtable 108 while the red color represented by the color indices 3, 4 and6 are combined into a single color index 3. All in all, for image 10,internal color mapping table 108 include three color indices: 1 forwhite, 2 for blue and 3 for red. As can be seen, output compositePostScript file 100 can be readily edited for three color indices 1, 2and 3 instead of six color indices 1 to 6. In particular, it should benoted that the script section for color index 3 includes vectorial pathsfor representing rectangle 16 and square 18 and a vectorial rectanglefor representing rectangle 22.

Turning now to FIG. 11, the conversion can include the step of scanningthe lines of input CEPS image data file 24 in bands such that the stepsof sorting the RLE entries by color into clusters of RLE entries andtranslating each cluster of RLE entries into one or more PDL elementsare performed band-by-band. Typically, a band includes between about 200and 1000 lines. In the present instance, image 10 is divided in twobands of 10 lines each. As can be seen, output composite PostScript file100 can be readily edited for scanning band-by-band. It should be notedthat the selection of one of the colors for use as the background coloris also done on a band-by-band basis. In this case, the color white isthe background color in both Band 0 and Band 1.

Turning now to FIG. 12, the conversion can include the step of matchingthe resolution of input CEPS LineWork image file 24 to the resolution ofan intended PostScript output device. This matching is achieved bymultiplying the resolution of input CEPS LineWork image data file 24 bythe ratio of the resolution of intended PostScript output device to theresolution of input CEPS LineWork image data file. For the sake ofexample, the resolution of an intended PostScript output device 170 isshown to be twice the resolution of input CEPS LineWork image data file24 (150). As can be seen in sample code 180, output composite PostScriptfile 100 can be readily edited to describe scaled LineWork image datafile 160.

Furthermore, in this case, the conversion can include the step ofmatching the user space of output composite PostScript file 100 with thedevice space of the intended PostScript output device. As known in theart, user space refers to locations within the PostScript page whiledevice space refers to locations within the final bitmap of the outputdevice. Transformations between the user space and the device spacenormally include a scale factor from the user space units, normally1/72", to the device space units in pixels, a translation component fromthe user space origin to device space origin and possible rotation andreflection components. Mathematically, the transformation is carried outby a 3×3 matrix called the Current Transformation Matrix (CTM). In orderto match the user space of the pseudo PS page to the output devicespace, the LineWork pixels are adopted as the user space units and thescale factor is reduced to 1, thus mapping one LineWork pixel to exactlyone device pixel. The other components of the transformation are keptintact.

With reference now to FIG. 13, the method for conversion of an inputCEPS image data file, for example, CEPS LineWork image data file 24, toan output separated PostScript file 200 according to the teachings ofthe present invention is now described with reference to image 10.

Generally speaking, output separated PostScript file 200 has a similarformat to separated PostScript file 32 in that it includes a prologsection 202, a set-up section 204 and four sections 206, 208, 210 and212 for each CMYK separation. However, in sharp contrast to nativeseparated PostScript file 32, each of sections 206, 208, 210 and 212typically includes a number of sub-sections dedicated to different graylevels of the CMYK separation ranging from white to solid color. Thesub-section dedicated to the white value of the CMYK separation istypically represented as a square of background color.

The conversion is similar to the conversion from CEPS LineWork imagedata file 24 to output composite PostScript file 100. The differencebeing that the sorting of Linework RLE entries into clusters is by CMYKseparation rather than by color (or color index) or, more accurately, byparticular values of CMYK separations. Hence, the number of clusters foreach CMYK separation corresponds to the number of values there are foreach CMYK separation. In the example given hereinbelow, there are onlytwo clusters for each CMYK separation because the values of the CMYKcomponents are either 0 or 1. However, it should be noted that eachcluster can be translated into one or more PostScript elements as willbecome clearer hereinbelow. Furthermore, it should be noted that thesame optimization techniques which can be applied to output compositePostScript file 100 can be applied to output separated PostScript file200 except for color mapping which is inherent to the separated mode.

Hence, in the present instance, cyan section 206 includes a sub-section206a representing white on the cyan separation and a sub-section 206brepresenting solid color on the cyan representation. Sub-section206bdescribes a path including sixteen sub-paths of which the first foursub-paths represent the cyan component of triangle 14 while the nexttwelve sub-paths represent the cyan component of triangle 20. While,magenta section 208 includes a sub-section 208a representing white onthe magenta separation and a sub-section 208b representing solid coloron the magenta representation. In this case, sub-section 208b includes apath having 22 sub-paths representing the magenta component of triangle14, rectangle 16, square 18 and triangle 20 and a rectangle representingthe magenta component of rectangle 22. It should be noted that the thirdand fourth sub-paths are concatenations of sub-paths originally fromtriangle 14 and rectangle 16. While, yellow section 210 includes asub-section 210a representing white on the yellow separation and asub-section 210b representing solid color on the yellow representation.In this case, sub-section 210b includes a path having 8 sub-paths forrepresenting the yellow component of rectangle 16 and square 18 and arectangle for representing the yellow component of rectangle 22. Andwhile, black section 212 includes a sub-section 212a representing whiteon the black separation.

With reference now to FIG. 14, the method for conversion of an CEPS pageto an output composite PostScript file 300 according to the teachings ofthe present invention is now described with reference to page 54. Asmentioned hereinabove, page 54 is described by CEPS LineWork image datafile 56 and Continuous Tone image data file 58. The conversion can bebest treated in two parts. First, the conversion of Continuous Toneimage data file 58 and second the conversion of LineWork image data file56. In the case that page 54 is also described by HC image data, the HCimage data is preferably converted into LineWork format such that it canbe treated as LineWork image data.

The first step of the conversion includes importing a portion ofContinuous Tone image data file 58 into a memory and extractingparameters from Continuous Tone image data file 58 required forreparation of prolog section 302 and set-up section 304 of outputcomposite PostScript file 300. Such parameters typically include theposition, dimensions and resolution of Continuous Tone image 58.

The second step of the conversion includes importing a portion ofLineWork image data file 56 into the memory and extracting parametersrequired for preparation of prolog section 302 and set-up section 304 ofPostScript file 300. Such parameters typically include page set-updetails including, but not limited to, LW image height, LW image width,and the LW image resolution. Preferably, this step of the conversionincludes importing LineWork color mapping table 60, if available.

The third step of the conversion includes preparing output compositePostScript file 300 and transferring the Continuous Tone image data fromContinuous Tone image data file 58 to a Continuous Tone section 305 inoutput composite PostScript file 300.

The fourth step of the conversion is the conversion of LineWork imagedata file 56 which is performed in a similar manner to the conversion ofLineWork image data file 24 as described with reference to outputcomposite PostScript file 100. The difference being that the transparentcolor, in this case designated by color index 3, is not converted suchthat script section 306 includes five sub-sections 306a, 306b, 306d,306e and 306f for color indices 1, 2, 4, 5 and 6 and does not includes asub-section 306c for color index 3. However, rectangle 16 is usedimplicitly to prevent the optimization of applying a rectangle ofbackground color to the whole page area because such a rectangle wouldsuperimpose some or all of the CT image. In this case, the backgroundcolor is defined as two rectangles and a path covering the whole pageexcept for the area defined as rectangle 16. As mentioned before,transparent colors can be semi-transparent which entails that adedicated technique using the overprint concept defined in PostScript.

The fifth and last step of the conversion is the exporting of the PDLelements to output composite PostScript file 300. As mentionedhereinabove, output composite PostScript file 300 can be a physical fileor, alternatively, it can be a stream of Page Description Language codetransmitted to a RIP, a computer, a workstation, and the like.

With reference now to FIG. 15, the method for conversion of an CEPS pageto an output separated PostScript file 400 according to the teachings ofthe present invention is now described with reference to page 54. Asmentioned hereinabove, page 54 is described by CEPS LineWork image datafile 56 and Continuous Tone image data file 58. Broadly speaking, theconversion can be regarded as a hybrid of the conversion of CEPSLineWork image data file 24 to output separated PostScript file 200 andthe conversion of Continuous Tone image data file 58.

Hence, generally speaking, output separated PostScript file 400 has asimilar format to output separated PostScript file 200 in that itincludes a prolog section 402, a set-up section 404 and four sections406, 408, 410 and 412 for each CMYK separation. However, in contrast tooutput separated PostScript file 200, each of sections 406, 408, 410 and412 typically includes a sub-section denoted "a" dedicated to CT image52. Furthermore, rectangle 16 is used as described hereinabove withreference to output composite PDL file 300.

Hence, in the present instance, cyan section 406 includes a sub-section406a representing the cyan contribution in CT image 52 on the cyanseparation, a sub-section 406b representing white on the cyanrepresentation and a sub-section 406c representing solid color on thecyan representation. While, magenta section 408 includes a sub-section408a representing the magenta contribution in CT image 52 on the magentaseparation, a sub-section 408b representing white on the magentaseparation and a sub-section 408c representing solid color on themagenta representation. While, yellow section 410 includes a sub-section410a representing the yellow contribution in CT image 52 on the magentaseparation, a sub-section 410b representing white on the magentaseparation and a sub-section 410c representing solid color on themagenta separation. And while, black section 412 includes a sub-section412a representing the black contribution in CT image 52 and asub-section 412b representing white on the black separation.

While the invention has been described with respect to a limited numberof embodiments, it will be appreciated that many variations,modifications and other applications of the invention may be made.

What is claimed is:
 1. A method of converting a Color ElectronicPre-press System (CEPS) LineWork (LW) image data file to a compositePage Description Language (PDL) file, the CEPS LineWork image data fileincluding a LineWork image made up of a multiplicity of LineWork runlength encoded (RLE) entries, the LineWork image featuring dimensionsand resolution, the method comprising the steps of:(a) importing aportion of the LineWork image data file into the memory, said portion ofthe data including parameters associated with the dimensions andresolution of the LineWork image; (b) reading parameters from theportion of the LineWork image data file associated with the dimensionsand resolution of the LineWork image; (c) preparing the composite PDLfile according to the parameters from step (b); (d) reading a pluralityof LineWork RLE entries from the CEPS LineWork image data file; (e)sorting the plurality of LineWork RLE entries by color into clusters ofLineWork RLE entries, such that the cluster of the color having thegreatest number of RLE entries is applied as a background color; (f)translating each cluster of LineWork RLE entries into at least one PDLelement realized as a concatenation of horizontal line segments; and (g)exporting each PDL element to the composite PDL file.
 2. A method ofconverting a Color Electronic Pre-press System (CEPS) LineWork (LW)image data file to a composite Page Description Language (PDL) file, theCEPS LineWork image data file including a LineWork image made up of amultiplicity of LineWork run length encoded (RLE) entries, and theLineWork image data file being made up of a plurality of bands, saidbands being made up of a plurality of LineWork lines, the LineWork imagefeaturing dimensions and resolution, the method comprising the stepsof:(a) importing a portion of the Linework image data file into thememory, said portion of the data including parameters associated withthe dimensions nd resolution of the LineWork image; (b) readingparameters from the portion of the LineWork image data file associatedwith the dimensions and resolution of the LineWork image; (c) preparingthe composite PDL file according to the parameters from step (b); (d)reading a plurality of LineWork RLE entries from the CEPS LineWork imagedata file; (e) sorting the plurality of LineWork RLE entries by colorinto clusters of LineWork RLE entries; (f) translating each cluster ofLineWork RLE entries into at least one PDL element realized as aconcatenation of horizontal line segments; (g) exporting each PDLelement to the composite PDL file; and (h) defining the number ofLineWork lines in a band and repeating steps (d) to (g) for each bandsuch that all the LineWork image data file is read.
 3. A method ofconverting a Color Electronic Pre-press System (CEPS) LineWork imagedata file to a separated Page Description Language (PDL) file, theLineWork image data file being made up of a plurality of bands, saidbands being made up of a plurality of LineWork lines, the separated PDLfile including a page for each Cyan, Magenta, Yellow and Black (CMYK)separation, the CEPS LineWork image data file including a LineWork imagemade up of a multiplicity of LineWork run length encoded (RLE) entries,the LineWork image featuring dimensions and resolution, the methodcomprising the steps of:(a) importing a portion of the Linework imagedata file into the memory, said portion of said data comprising dataassociated with the dimensions and resolution of the LineWork image; (b)reading parameters from the portion of the LineWork image data fileassociated with the dimensions and resolution of the LineWork image; (c)preparing the separated PDL file according to the parameters from step(b); (d) reading a plurality of LineWork RLE entries from the CEPSLineWork image data file; (e) preparing at least one cluster of LineWorkRLE entries for each CMYK component separately, each of the at least onecluster being dedicated to a particular value for that CMYK separationcolor; (f) translating each cluster of LineWork RLE entries into atleast one PDL element; (g) exporting each PDL element to itscorresponding CMYK script section of the separated PDL file; and h)defining the number of LineWork lines in a band and repeating steps (d)to (g) for each band such that all the LineWork image data file is read.4. A method of converting a Color Electronic Pre-press System (CEPS)LineWork image data file to a separated Page Description Language (PDL)file, the separated PDL file including a page for each Cyan, Magenta,Yellow and Black (CMYK) separation the CEPS LineWork image data fileincluding a LineWork image made up of a multiplicity of LineWork runlength encoded (RLE) entries, the LineWork image featuring dimensionsand resolution, the method comprising the steps of:(a) importing aportion of the LineWork image data file into the memory, said portion ofsaid data comprising data associated with the dimensions and resolutionof the LineWork image; (b) reading parameters from the potion of theLineWork image data file associated with the dimensions and resolutionof the LineWork image; (c) preparing the separated PDL file according tothe parameters from step (b); (d) reading a plurality of LineWork RLEentries from the CEPS LineWork image data file; (e) preparing at leastone cluster of LineWork RLE entries for each CMYK component separately,each of the at least one cluster being dedicated to a particular valuefor that CMYK separation color; (f) sorting at least one cluster foreach CMYK component, said sorting producing clusters of individual CMYKcomponents, wherein the cluster of an individual CMYK separation colorhaving the greatest number of RLE entries is applied as a backgroundcolor; (g) translating each cluster of LineWork RLE entries into atleast one PDL element; and (h) exporting each PDL element to itscorresponding CMYK script section of the separated PDL file.
 5. A methodof converting a Color Electronic Pre-press System (CEPS) page describedby a LineWork image data file and a Continuous Tone image data file to acomposite Page Description Language (PDL) file, the LineWork image datafile including LineWork image made up of multiplicity of LineWork runlength encoded (RLE) entries of which at least one entry has atransparent color value associated with a Continuous Tone image, themethod comprising the steps of:(a) importing a portion of the ContinuousTone image data file into a memory said portion of data including dataassociated with the position, dimensions and resolution of theContinuous Tone image; (b) reading parameters from the portion of theContinuous Tone image data file associated with the position, dimensionsand resolution of the Continuous Tone image; (c) importing a portion ofthe LineWork image data file into the memory, said portion of dataincluding data associated with the dimensions and resolution of theLineWork image; (d) reading parameters from the portion of the LineWorkimage data file associated with the dimensions and resolution of theLineWork image; (e) preparing the composite PDL file according to theparameters from steps (b) and (d); (f) transferring Continuous Toneimage data from the Continuous Tone image data file to the composite PDLfile; (g) reading a plurality of LineWork RLE entries from the LineWorkimage data file; (h) sorting the plurality of LineWork RLE entries bycolor into clusters of LineWork RLE entries, wherein the clusters aresorted such that the cluster of the color having the greatest number ofRLE entries is applied as a background color in all areas except fortransparent areas; (i) translating each cluster of LineWork RLE entriesinto at least one PDL element except for the clusters having transparentcolor values; and (j) exporting each PDL element to the composite PDLfile.
 6. A method of converting a Color Electronic Pre-press System(CEPS) page described by a LineWork image data file and a ContinuousTone image data file to a composite Page Description Language (PDL)file, the LineWork image data file being made up of a plurality ofbands, said bands being made up of a plurality of LineWork lines and theLineWork image data file including a LineWork image made up of amultiplicity of LineWork run length encoded (RLE) entries of which atleast one entry has a transparent color value associated with aContinuous Tone image, the method comprising the steps of:(a) importinga portion of the Continuous Tone image data file into a memory, saidportion of data including data associated with the position, dimensionsand resolution of the Continuous Tone image; (b) reading parameters fromthe portion of the Continuous Tone image data file associated with theposition, dimensions and resolution of the Continuous Tone image; c)importing a portion of the LineWork image data file into the memory,said portion of data including data associated with the dimensions andresolution of the LineWork image; (d) reading parameters from theportion of the LineWork image data file associated with the dimensionsand resolution of the LineWork image; (e) preparing the composite PDLfile according to the parameters from steps (b) and (d); (f)transferring Continuous Tone image data from the Continuous Tone imagedata file to the composite PDL file; (g) reading a plurality of LineWorkRLE entries from the LineWork image data file; (h) sorting the pluralityof LineWork RLE entries by color into clusters of LineWork RLE entries;(i) translating each cluster of LineWork RLE entries into at least onePDL element except for the clusters having transparent color values; (j)exporting each PDL element the composite PDL file; ad (k) defining thenumber of LineWork lines in a band and repeating steps (g) to (j) foreach band such that all the LineWork image data file is read.
 7. Amethod of converting a Color Electronic Pre-press System (CEPS) pagedescribed by a LineWork image data file and a Continuous Tone image datafile to a separated Page Description Language (PDL) file, the LineWorkimage data file being made up of a plurality of bands, said bands beingmade up of a plurality of LineWork lines, and the LineWork image datafile including a LineWork image made up of a multiplicity of LineWorkrun length encoded (RLE) entries of which at least one entry has atransparent color value associated with a Continuous Tone image, themethod comprising the steps of:(a) importing a portion of the ContinuousTone image data file into a memory, said portion of data including dataassociated with the position, dimensions and resolution of theContinuous Tone image; (b) reading parameters from the portion of theContinuous Tone image data file associated with the position, dimensionsand resolution of the Continuous Tone image; (c) importing a portion ofthe LineWork image data file into the memory, said portion of dataincluding data associated with the dimensions and resolution of theLineWork image; (d) reading parameters from the portion of the LineWorkimage data file associated with the dimensions and resolution of theLineWork image; (e) preparing the separated PDL file according to theparameters from steps (b) and (d); (f) transferring the Continuous ToneImage data from the Continuous Tone image data file to the separated PDLfile for the first of the Cyan, Magenta, Yellow and Black (CMYK)components; (g) reading a plurality of LineWork RLE entries from theLineWork image data file; (h) preparing at least one cluster of LineWorkRLE entries from the CMYK component selected in step (f), each of the atleast separation color; (i) translating each cluster of LineWork RLEentries into at least one PDL element except for clusters havingtransparent color values in that separation; (j) exporting each PDLelement to its corresponding CMYK script section of the separated PDLfile; (k) repeating steps (f) through (j) for the other CMYK components;and (l) defining the number of LineWork lines in a band and repeatingsteps (g) to (j) for each band such that all the LineWork image datafile is read.
 8. A method of converting a Color Electronic Pre-pressSystem (CEPS) page described by a LineWork image data file and aContinuous Tone image data file to a separated Page Description Language(PDL) file, the LineWork image data file including a LineWork image madeup of a multiplicity of LineWork run length encoded (RLE) entries ofwhich at least one entry has a transparent color value associated with aContinuous Tone image, the method comprising the steps of:(a) importinga portion of the Continuous Tone image data file into a memory, saidportion of data including data associated with the position, dimensionsand resolution of the Continuous Tone image; (b) reading parameters fromthe portion of the Continuous Tone image data file associated with theposition, dimensions and resolution of the Continuous Tone image; (c)importing a portion of the LineWork image data file into the memory,said portion of data including data associated with the dimensions andresolution of the LineWork image; (d) reading parameters from theportion of the LineWork image data file associated with the dimensionsand resolution of the LineWork image; (e) preparing the separated PDLfile according to the parameters from steps (b) and (d); (f)transferring the Continuous Tone image data from the Continuous Toneimage data file to the separated PDL file for the first of the Cyan,Magenta, Yellow and Black (CMYK) components; (g) reading a plurality ofLineWork RLE entries from the LineWork image data file; (h) preparing atleast one cluster of LineWork RLE entries from the CMYK componentselected in step (f), each of the at least one cluster being dedicatedto a particular value for that CMYK separation color; (i) sorting the atleast one cluster for each CMYK component, said sorting producingclusters of individual CMYK components, wherein the cluster of the CMYKseparation color having the greatest number of RLE entries is applied asa background color in all areas except for the transparent areas; (j)translating each cluster of the LineWork RLE entries into at least onePDL element except for clusters having transparent color values in thatseparation; (k) exporting each PDL element to its corresponding CMYKscript section of the separated PDL file; and (l) repeating steps (f)through (k) for the other CMYK components.